As many as 13,000 people, most of them civilian opposition supporters, have been executed in secret at a prison in Syria, Amnesty International says.

    A new report by the human rights group alleges that mass hangings took place every week at Saydnaya prison between September 2011 and December 2015, the (BBC) reported.

    Amnesty says the alleged executions were authorised at the highest levels of the Syrian government. The government has previously denied killing or mistreating detainees.

    However, UN human rights experts said a year ago that witness accounts and documentary evidence strongly suggested that tens of thousands of people were being detained and that "deaths on a massive scale" were occurring in custody.

    Amnesty interviewed 84 people, including former guards, detainees and prison officials for its report. It alleges that every week, and often twice a week, groups of between 20 and 50 people were executed in total secrecy at the facility, just north of Damascus.

    Amnesty says these practices amounted to war crimes and crimes against humanity.

Source: QNA